The invention relates generally to electrical connectors and, more particularly, to a connector that may be used in an orthogonal relationship with an identical connector on both sides of a midplane.
Some electrical systems, such as network switches or a computer server with switching capability, include large backplanes with several switch cards and line cards plugged into the backplane. Generally, the line cards bring data from external sources into the system. The switch cards contain circuitry that may switch data from one line card to another. Traces in the backplane interconnect the line cards and the appropriate switch cards.
Some signal loss is inherent in a trace through printed circuit board material. As the number of card connections increases, more traces are required in the backplane. The increased number of traces and the length of the traces in the backplane introduce more and more signal loss in the backplane, particularly at higher signal speeds. Signal loss problems may be addressed by keeping traces in the backplane as short as possible.
Connectors are sometimes oriented orthogonally on both sides of a midplane in a cross connect application in an effort to minimize the number and lengths of traces in the midplane. Typically, switch cards are connected on one side of the midplane and line cards are connected on the other side. The connectors can have any of several transmission line geometries, and in some cases, a coplanar transmission line geometry is used, wherein signal and grounds are arranged in a spaced apart relationship in a common plane. The line card and switch card connectors are typically mounted on the midplane through vias that extend through the midplane. Connectors oriented orthogonally may allow at least some traces to be eliminated, however, the unused length of the vias, referred to as the via stubs, at the signal connections act as filters which also cause signal loss. Thus, the interconnection of line cards and switch cards through a backplane or midplane with minimal signal loss remains a challenge.